The invention relates in general to wireless communication systems and more specifically to control signals in a wireless communication system.
Base stations in cellular communication systems provide communications services to wireless communication devices within geographical cells where each base station exchanges signals with wireless communication devices within an associated cell. The size and shape of each cell and, therefore, the coverage area of the base station are determined by several factors and are at least partially based on design parameters of the base station. In addition to large macro cells that provide services to numerous devices within relatively large geographical areas, some cellular communication systems are increasingly employing smaller cells to increase efficiency, improve coverage, improve the quality of service, and provide additional services. The smaller cells may include a variety of sizes typically referred to as microcells, picocells and femtocells. Microcells and picocells are often implemented within office buildings, shopping centers and urban areas in order to provide additional security, higher user capacity for the area, additional service features, and/or improved quality of service. Femtocells have relatively smaller geographical areas and are typically implemented at residences or small office locations. Since typical cellular backhaul resources may not be available in these locations, femtocells are sometimes connected to the cellular infrastructure through DSL or cable modems. Femtocells are part of the cellular network and, therefore, communicate with the wireless devices using the same techniques as those used by macrocells. The proximity of the various base stations and wireless communication devices often results in interference. In addition to interference of data communications, control channels may also suffer performance degradation due to interference. Further, identical control information is often transmitted by multiple base stations.